Oscillation suppression in a particle robotic arm by stiffness and damping regulation

Abstract

Flexible arms have been widely studied by researchers in recent years, because of their adaptability and interactive security. Due to the low stiffness of the flexible arms, there will be large position deviation and long-period oscillation during de-actuated or excited, which is undesirable in many applications. This paper introduces the design principle and manufacturing method of a flexible arm with variable stiffness and damping to suppress oscillations. The arm is composed of three thin McKibben pneumatic artificial muscles and a chamber filled with discrete particles. The end position is determined by the air pressure input to the artificial muscles, the stiffness and damping of the arm can be further controlled by the vacuum pressure in the particle chamber. Models for stiffness, damping, and the effects on the oscillation suppression of the arm are established, and their validity is verified experimentally. Moreover, the significance of oscillation suppression in the proposed arm is proved by an image stabilization system.